In the first two ‘Going Mobile’ posts we explored how cross-device matching works and how ads are targeted and delivered to those users. In this long overdue post, we’ll go from the theoretical to the practical and go through some best practices for getting the most from your cross-device retargeting campaigns.

1. Figure out what your goals are

This is the basic step that should kick off any marketing campaign. Determine what you want to accomplish. Cross-device retargeting can help you accomplish four general goals:

• Build awareness: Do you want to keep your brand in front of your potential customers at the right moments?

• Facilitate acquisition: Did your visitor view a category or a product on your web site? Is there a potential next step you want to encourage?

• Drive conversions: Did the person abandon her shopping cart? Could a little push help complete the transaction?

• Reengage: Is there potential for reengaging with existing customers to either cross-sell complementary products or encourage a repeat purchase?

2. Segment your audiences

Creating actionable audience segments is necessary for any retargeting campaign and it’s no different when you’re retargeting users on their mobile devices. When segmenting your audiences, there’s a balance you’ll need to strike with your audience segments – smaller audiences can perform well, but are harder to scale; large, generic audiences can be harder to optimize. For cross-device retargeting campaigns, we’d recommend starting with the following audiences:

• All visitors

• Visitors who have viewed a product or category

• Visitors who have abandoned their shopping carts

• Customers (people who have converted)

3. Choose the right ad format

If you’ve ever done retargeting, the previous two steps should be pretty familiar already. Step three is where some of the nuances diverge. There are two common mobile ad formats used in-app and across mobile web sites:

• Mobile Banners display the ad across the bottom of the screen. The most common size for mobile banners is 320×50.

• Interstitial Ads take over the screen until the user dismisses it. The most common interstitial sizes are 320×480 or 480×320.

Beyond the obvious difference in size, the two ad formats have distinct strengths and weaknesses.

If you want to drive volume, mobile banners are your best bet, as the available inventory vastly outnumbers mobile interstitial inventory. We’ve typically seen the number of available banner impressions outnumber interstitial impressions by 3-5x. Mobile banners are also significantly cheaper than interstitials. Mobile banner CPMs range from $.50-$2.00+, whereas interstitial CPMs range from $3.00-7.00+. On average, interstitial campaign CPMs are about 3-6x higher than mobile banner CPMs.

Of course, price isn’t the only issue. Part of the reason Mobile Interstitial ads cost more is because they enjoy significantly higher engagement rates. On average, interstitial click-through rates (CTRs) are 3-4x higher than banner CTRs. Based on the campaign and creative quality, we’ve even seen interstitial campaigns with CTRs up to 10x higher than average banner CTRs.

The takeaway here is that, as always, there are trade-offs so it’s worthwhile to test different formats to see which best addresses your specific goals. For scenarios where volume is important, or you’re budget constrained, try testing mobile banner ads. If you’re trying to encourage customer action, then interstitials might be the optimal format.

4. Optimize your creative for mobile

Provide a clear and simple value proposition; create a sense of urgency and include vivid, strong CTAs

• Use strong call-to-actions with bold designs. You have a split second to capture your audiences’ attention; don’t get cute with your CTAs. Use strong, directive language, and make sure the CTA design stands out.

• Create urgency. Mobile can be a particularly effective means to get users to take immediate action. Try including an element of limited timing or supply in your message.

• Rotate your creative. One of the benefits of mobile advertising is that there’s much less clutter and typically only one ad is shown on-screen at a time. The downside of this exclusivity is that your audience is likely to become tired of your creative much quicker. To minimize banner fatigue, try to create a couple different variations of each ad and rotate them liberally.

5. Measure holistically using view-through conversions

I’ve already beaten the drum pretty soundly on why you should be measuring view-through attribution here. If you’re still primarily measuring performance on a last-click model, mobile might be a good opportunity to also try testing a view-through attribution model. Tracking mobile view-throughs can be especially enlightening if your customers are more likely to convert on desktops or if your ad CTAs drive to a desktop-centric action.

Hopefully these recommendations will help you get a head start with your cross-device and mobile retargeting campaigns!